OPTICAL ENCODER

摘要

PURPOSE: An optical encoder is provided to obtain sine waves with reliability when suing a rotational scale by making the width of the inner periphery direction of a light receiving unit pattern or a scale pattern shorter than the width of the outer periphery thereof. CONSTITUTION: An optical encoder (100) comprises a scale (120) and a light receiving unit (140). A first pattern (130) is formed on the scale. The light receiving unit is relatively moved with respect to the scale, and a second pattern (141) is formed in the light receiving unit. At least one of the first and second patterns is formed into a band shape for obtaining sin wave signals. At least one of a partial outer line of the first and second patterns is formed into a sinusoidal wave form.